1. Field of the Invention
The present invention generally relates to a driver apparatus, in particular, to a gate driver apparatus of a liquid crystal display (LCD).
2. Description of Related Art
With the development of electronic technology, more and more multimedia devices with audio and video playback functions are provided. To both ensure the audio and video quality and reduce the cost and price of these products, many driving modes and circuits of displays have been developed. The displays include normal liquid crystal displays (LCDs), light emitting diode (LED) displays, and vacuum fluorescent displays (VFDs).
However, the driver apparatus of any of the above displays must provide a driving signal at a high voltage level for driving the corresponding display panel. Normally, a plurality of level shifters is needed to generate the driving signal at a high voltage level. FIG. 1 is a block diagram of a conventional gate driver apparatus 100 of an LCD. Referring to FIG. 1, a logic circuit 110 receives an input signal IP, and generates an internal control signal. The internal control signal is transmitted to a shift register 120. The logic circuit 110 and the shift register 120 are both formed by logic circuits, and thus operate in a relatively low voltage range (voltage VDD to GND).
To generate the driving signal at a voltage high enough to drive the display, a level shifter 130 transforms the voltage level of the internal control signal to between the voltage VDD and a voltage VEE, and a level shifter 140 transforms the voltage level of the internal control signal to between a voltage VCC and the voltage VEE. The voltage VEE is lower than the voltage GND, and the voltage VCC is higher than the voltage VDD. The gate driver apparatus 100 must drive the display on different channels, and the number of the required level shifters 130 and 140 is in direct proportion to the number of the channels. Therefore, the level shifters 130 and 140 occupy a large circuit area.